Bunashimeji mushroom plant named ‘Hokuto-18’

ABSTRACT

A new and distinct variety of mushroom plant of Bunashimeji mushroom,  Hypsizigus marmoreus , named ‘Hokuto-18’, is cultivated by gathering and repeated breeding of fungal strains having dominant traits. This new and distinct variety has good qualitative character and appearance, good keeping quality and storage life and delicious tasting and is exquisite in stability, reproducibility and uniformity when being produced.

Latin name of the genus and species of the plant claimed: Hypsizigusmarmoreus.

BACKGROUND OF THE INVENTION

This invention relates to a new and distinct variety of mushroom plantof Bunashimeji mushroom, Hypsizigus marmoreus. This new variety named‘Hokuto-18’ cultivated by repeated breeding of Bunashimeji mushroomshaving dominant traits, which is tasty and less bitter to the taste, hasexcellent quality, pleasing appearance, good keeping quality and storagelife and ensure stability, reproducibility and uniformity.

Whereas the Bunashimeji mushroom has been so far cultivated artificiallyand widely eaten, the Bunashimeji mushroom produced by gathering andartificially cultivating wild mushrooms tastes unpleasantly bitter.

The Bunashimeji mushroom has a cap (pileus) with mottles. The mottles ofthe artificially cultivated Bunashimeji mushroom take various forms suchas clear mottles, minute mottles or dilute mottles. The fine mottles,which are characteristic of the Bunashimeji mushroom, improve theappearance of the mushroom and prove to be good in quality. Thethicknesses of the stem and cap of the mushroom affect eating quality.It is of course that the mushroom having good eating quality is superiorin quality of goods. It is therefore significant to find suitablevarieties of mushroom out of wild Bunashimeji mushrooms in order toimprove the varieties as much as possible.

Furthermore, the perishable mushroom gradually deteriorates in flavorand quality when being preserved for a while after harvesting. Thus,there has been a need for mushrooms having good keeping quality andstorage life so as not to degrade their quality during the course ofdistribution. However, it is disadvantageously difficult to findsuitable fungal strains having good qualitative character and highquality from a huge variety of wild mushrooms gathered and screenedcarefully.

SUMMARY OF THE INVENTION

The present invention is a new and distinct variety of mushroomcharacterized particularly by its good qualitative character andappearance, good keeping quality and storage life and delicious tasting,which can be cultivated by gathering and repeated breeding of fungalstrains having dominant traits and is exquisite in stability,reproducibility and uniformity when being produced. This novel anddistinct variety of mushroom is identified as ‘Hokuto-18’.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1A shows a top view of new variety of mushrooms named ‘Hokuto-18’of the present invention.

FIG. 1B shows a bottom view of the mushrooms of FIG. 1A.

FIG. 1C shows a side view of the mushrooms of FIG. 1A.

FIG. 1D shows a side cutaway view of the mushrooms of FIG. 1A.

FIG. 2A shows the state of cultivating the ‘Hokuto-18’ mushrooms inbottles.

FIG. 2B shows the ‘Hokuto-18’ mushrooms according to the invention.

FIG. 3 shows the state of cultivating in bottles a control variety‘Hokuto-8’ similar to the mushrooms of the invention.

FIG. 4 shows the state of cultivating in bottles a control variety‘Hokuto-16’ similar to the mushrooms of the invention.

FIG. 5 shows the state of juxtapositional cultivation of the ‘Hokuto-18’mushrooms placed in juxtaposition.

FIG. 6 shows characteristics of the ‘Hokuto-18’ mushrooms incultivation.

FIG. 7 shows the state of juxtapositional cultivation of the ‘HOKUTO-18’mushrooms and the control variety ‘Hokuto-8’.

FIG. 8 shows the state of juxtapositional cultivation of the ‘Hokuto-18’mushrooms and a control variety grown in Nagano, Japan.

FIG. 9 shows the state of juxtapositional cultivation of the ‘Hokuto-18’mushrooms and a control variety grown in Niigata of Japan.

FIG. 10 is a graph showing differences in growth of fungal hyphae amongthe ‘Hokuto-18’ mushrooms of the invention and control varieties‘Hokuto-8’ and ‘HOKUTO-16’.

FIG. 11 shows the states of the ‘Hokuto-18’ mushrooms of the inventionand control varieties grown in Nagano and Niigata of Japan, each on the9th, 13th and 17 days of growing.

FIG. 12 shows a comparison of ‘Hokuto-18’ to control varieties.

BOTANICAL DESCRIPTION

This invention relates to a new and distinct variety of mushroom plantof Bunashimeji mushroom, Hypsizigus marmoreus, named ‘Hokuto-18’, whichis cultivated by repeatedly breeding Bunashimeji mushrooms havingdominant traits. This new variety of mushroom is very tasty and notbitter, has excellent quality, pleasing appearance, good keeping qualityand storage life and ensure stability, reproducibility and uniformity.

The new variety ‘Hokuto-18’ according to the invention has beendeposited at “International Organism Depository” of National Instituteof Advanced Industrial Science and Technology under Deposit No. FERMP-20537.

One actual sample of the new variety ‘Hokuto-18’ of the invention isshown in FIGS. 1A through 1D. Needless to say, this illustrated sampleshould not be understood as one and only embodiment of the inventionbecause the subject matter of the invention is a plant having anundefined figure. The morphological characteristics of the new variety‘Hokuto-18’ of the invention will be described in detail later.

The new variety ‘Hokuto-18’ of the invention is produced from twoparental cultivars, each cultivated by repeatedly breeding Bunashimejimushrooms. One of the parental cultivars was produced and uniquely named‘Hokuto Jyurokugokin’ (‘Hokuto-16’), and another cultivar is whiteBunashimeji mushrooms, which was likewise produced and uniquely named‘Hokuto Shiro Ichigoukin’.

The parental cultivar ‘Hokuto-16’ was obtained by breeding of ‘HokutoJyuichigokin’ (‘Hokuto-11’), which has been registered in the JapanesePlant Variety Register under Variety Registration No. 12049 on Mar. 15,2004, and fungal strains uniquely code-named ‘MH025143’ . ‘Hokuto-16’has not been patented in the United States.

The ‘Hokuto Shiro Ichigoukin’ was obtained by breeding of a variety‘Hokuto Hachigoukin’ (‘Hokuto-8’), which was once registered in theJapanese Plant Variety Register, and a variety ‘Hokuto Jyunigoukin’(‘Hokuto-12’) registered in the Japanese Plant Variety Register underVariety Registration No. 10749 and exposing the varieties thus bred toultraviolet rays to consequently turn whiter or lighter. The ‘HokutoShiro Ichigoukin’ has been registered in the Japanese Plant VarietyRegister under Variety Registration No. 13294. This variety has beenapplied for a United States patent and published under No. 20040025215,now plant patent 16,294, issued Feb. 28, 2006.

The processes of breeding and cultivating ‘Hokuto-18’ according to theinvention will be described hereinafter.

[Breeding Process of ‘Hokuto-18’].

First, four kinds of Bunashimeji mushrooms gathered in Japan werecrossed repeatedly to produce the aforementioned ‘Hokuto-16’ and whiteBunashimeji mushrooms ‘Hokuto Shiro Ichigoukin’ before October 2001.

The ‘Hokuto-16’ has good morphological characters, i.e. fleshy stem andcap, clear mottles and good quality, but it has poor keeping quality.Meanwhile, the white Bunashimeji mushroom is superior in quality andkeeping quality and storage life and different in whiteness fromexisting Bunashimeji mushrooms.

Crossbreeding of ‘Hokuto-16’ and white Bunashimeji mushrooms wasperformed to develop 628 new breed strains of mushrooms in April 2003.Then, cultivation experiments were carried out for verifying the traitcharacters of these breed strains thus developed in October 2003,consequently to chase up adequate fungal strains (named ‘03HM009’)having good quality, taste and keeping quality.

Thereafter, further cultivation experiments were repeatedly carried outstarting from December 2003 for corroborating stability, reproducibilityand uniformity of the new strains, and as a result, proved confirmationthat the new fungal strains were fit for the expected purpose of theinvention, thus to be named ‘Hokuto-18’ strains ultimately. The newfungal strain ‘Hokuto-18’ has been applied for a plant varietyregistration under the Japanese Seeds and Seedlings Law on Aug. 19, 2004(Application No. 17353).

[Traits of new fungal strain ‘Hokuto-18’].

-   -   (1) Comparison with existing varieties injuxtapositional        cultivation:

Juxtapositional cultivation experiments were performed several times,placing the parental cultivar of ‘Hokuto-18’ strain and commerciallyavailable varieties in juxtaposition with each other, for observing thereluctant reaction caused when the fungal strains are extraneous to eachother. As a result, the juxtapositional cultivation experiments haveshown that the parental cultivar of ‘Hokuto-18’ was extraneous to allthe existing varieties (see Table 1 below).

TABLE 1 Results of juxtapositional cultivation experiments Controlvarieties available in the market Similar control varieties Nagano-grownNiigata-grown ‘Hokuto-16’ ‘Hokuto-8’ variety variety ‘Hokuto- + + + +18’

The variety ‘Hokuto-8’ shown in Table 1 was cultivated by breeding oftwo fungal strains naturally grown in a mountain in Nagano of Japan inMarch 1992.

The control variety, Bunashimeji mushroom, grown in Nagano of Japan wascommercially available from a supermarket in Japan. Another controlvariety, Bunashimeji mushroom, grown in Niigata of Japan was alsocommercially available from a supermarket in Japan.

The experiments for the aforementioned reluctant reaction were performedby inoculating the ‘Hokuto-18’ strains and the control strains on apotato dextrose agar medium with a distance of 3 centimeters. Afterconducting the cultivation at 25° C. for 28 days, the reluctant reactionof the testing strains was measured. The results of the experiments forthe reluctant reaction confirmed that the ‘Hokuto-18’ of the inventionis new and distinct.

The state of cultivating the ‘Hokuto-18’ mushrooms in bottles is shownin FIGS. 2A, 2B, 3 and 4.

-   -   (2) Cultural characteristics of ‘Hokuto-18’.

(a) When the ‘Hokuto-18’ strain was cultivated on a malt extract agarmedium, it was roundly grown so that the fungal threads thereof weregrown to 36.98 mm for ten days. The ‘Hokuto-18’ strain resultantly grownhas white fungal threads brought up densely with a great number ofaerial hyphae.

(b) When the ‘Hokuto-18’ strain was cultivated on a potato dextrose agarmedium, it was roundly grown so that the fungal threads thereof weregrown to 36.69 mm for ten days. The ‘Hokuto-18’ strain resultantly grownhas white fungal threads brought up densely with a great number ofaerial hyphae.

(c) After inoculating the seed fungi of ‘Hokuto-18’ strain of 5 mm indiameter on the potato dextrose agar medium, the cultivation of thestrain was conducted at intervals of 5° C. within 5° C. to 35° C.Measurement of growth of the fungal threads of the strain on thecultivating experiments conducted for 15 days showed much more growth ofthe fungal threads per day at 25° C.

-   -   (3) Morphological characteristics of ‘Hokuto-18’ cultivated        experimentally.

[Cultivation method] The cultivation was conducted using a bottlecontaining sawdust culture medium. The bottle of polypropylene, having acapacity of 800 cc, was used. The culture medium used in the cultivationwas prepared by mixing sawdust of broad leaf tree and cedar as a carrierwith rice bran by three to one and adding water to the carrier to 65% ofmoisture content of the carrier. The culture medium thus prepared wassterilized by heating at a high temperature of 120° C. for 40 minutesunder high pressure, and then, cooled to about 20° C. Thereafter, theseed fungi were inoculated on the culture medium thus prepared, andtherefore, cultivated at 20° C. for 70 days. (The same culture medium asabove was used.) Upon completion of cultivation, fungus scratching onthe culture medium and sprouting of the seed fungi were performed at atemperature of 15° C. and at a humidity of 90% to breed fungal strains.After gemmation, the fungal strains thus bred were further nurtured at atemperature of 15° C., at a humidity of 95% and at an illuminationintensity of 100 Lux. Then, resultantly grown mushrooms were harvestedwhen the caps thereof reach maturity.

The new variety ‘Hokuto-18’ grown in the manner as described above hasthe following trait characteristics. The ‘Hokuto-18’ has a pileus (cap)with an arched top having a central part of yellow tea color and aperipheral part of isabella color. Distinct mottles are distributed allover the upper surface of the fungous pileus except for the peripherythereof. The gills of the fungus are white and normal. The stem iswhite, shortish, eccentric to the cap and not hairy and has amedium-sized diameter. Eventually there could be harvested 56 strainshaving a weight of about 111.1 grams on an average and a length of over2 centimeters.

The distinct differences in trait characters of the new variety‘Hokuto-18’ and most similar variety are shown in Table 2 below:

TABLE 2 Differences in trait between ‘Hokuto-18’ and similar varieties(Comparison of ‘Hokuto-18’ with similar control varieties) Character‘Hokuto-18’ ‘Hokuto-8’ ‘Hokuto-16’ Genetic type of fruit Aggregatus formAggregatus Disparate body form form Effective number of 111 103 125Stems Yield (grams per strain) 56 66 49 Diameter of pileus 19.4 18.023.1 (mm) Color of central part¹ Yellow tea Taupe Taupe Color of fringepart¹ Isabella Pale taupe Pale taupe Fleshy substance Middle Soft MiddleFleshy thickness (mm) 5.7 5.1 6.4 Quantity of mottles Middle Many MiddleSize of mottles Middle Small Middle Spread of mottles Except fringeCentral part Except part fringe part Clearness of mottles Clear NormalNormal Gill (Color)¹ White Whity- White yellow Stem (Length (mm)) 41.942.5 56.6 Color¹ White Whity- White yellow Ratio of maximum 1.85 2.1 1.7diameter of stem to diameter just below cap Ratio of cap diameter to2.35 2.16 2.45 stem diameter ¹Color chart: Royal Horticultural Society.Fifth Edition

The differences in growth of fungal hyphae among the new variety‘Hokuto-18’ and control varieties ‘Hokuto-8’ and ‘Hokuto-16’ are shownin Table 3 and FIG. 10.

TABLE 3 Differences in growth of fungal hyphae Measurement of growth ofthe fimgal threads at intervals of 5° C. (mm/day) Temperature (° C.)Strain Name 5 10 15 20 25 30 35 ‘Hokuto-18’ 0.7 1.3 2.0 3.1 3.7 2.5 0.0‘Hokuto-6’ 0.7 1.3 1.9 3.0 4.1 2.9 0.0 ‘Hokuto-8’ 0.7 1.4 2.0 3.3 3.92.6 0.0 Analysis of optimum temperature Strain Name Temperature (° C.)Growth of fungal threads (mm) ‘Hokuto-18’ 24.2 3.7 ‘Hokuto-6’ 25.0 4.1‘Hokuto-8’ 24.2 3.9

-   -   (4) Eating-quality characteristics (Table 4)

The new variety ‘Hokuto-18’ was compared in eating-qualitycharacteristics with control varieties available in the market. The newvariety ‘Hokuto-18’ and the control varieties are shown in FIG. 12.

First, Bunashimeji mushroom samples each having a fruit body of 100grams were heated in a microwave oven (500W) for 70 minutes, and then,cooled at room temperature. Thereafter, blind tasting tests wereconducted among 30 tasting testers to confirm the taste of the newvariety ‘Hokuto-18’ compared to the control varieties available in themarket with respect to daintiness, bitterness and firmness. The resultof the tasting tests is shown in Table 3. As is evident from the tastingresult, the new variety ‘Hokuto-18’ was assessed by almost all oftasting testers as delicious, not bitter and pleasingly crunchy comparedto the control varieties.

TABLE 4 Numbers of testers who made valuations of the varietiesDaintiness Bitterness Firmness No Not Not Good good Bitter bitterCrunchy crunchy ‘Hokuto-18’ 30 0 2 28 22 8 Nagano-grown 16 14 14 16 1218 variety Niigata-grown 24 6 8 22 22 8 variety

Out of 30 tasting testers, 100% appraised as delicious. 93% of thetesters appraised ‘Hokuto-18’ as not bitter. The tasting results showthat the new variety ‘Hokuto-18’ is deliciously flavored.

-   -   (5) Keeping quality of ‘Hokuto-18’ (Table 5)

Preservation tests were carried out using the new variety ‘Hokuto-18’and the control varieties available in the market. The preservationtests were conducted by packaging the varieties after harvesting toprepare 20 test packs, keeping the test packs in corrugated board boxesat 8° C. for 6 days, and further preserving them at 25° C. after the 7thday. The results of the preservation tests are shown in Table 5 below,showing that the quality of the new variety Hokuto-18 could becongruously kept in quality after the 12th day of harvesting as well.Thus, the new variety ‘Hokuto-18’ has apparently better keeping qualitythan the other existing varieties available in the market.

TABLE 5 Aspects of varieties after harvesting Elapsed days afterharvesting 6 7 8 9 10 11 12 13 14 15 16 17 18 ‘Hokuto- ∘ ∘ ∘ ∘ ∘ ∘ ∘ Δ ΔΔ Δ Δ x 18’ Nagano- ∘ ∘ ∘ Δ Δ Δ Δ x grown variety Niigata- ∘ ∘ ∘ Δ Δ Δ Δx grown variety ∘: Impeccable Δ: Abnormality occurring in one or moretest x: samples No commercial value

The results of the aforementioned preservation tests show that the newvariety ‘Hokuto-18’ has good keeping quality.

The juxtapositional cultivations shown in FIG. 5 through FIG. 9 weremade using the new variety ‘Hokuto-18’ of the invention, the controlvarieties ‘Hokuto-16’ and ‘Hokuto-8’, and commercially availablemushrooms. In the juxtapositional cultivation of two ‘Hokuto-18’ strainsof the same kind, the bacterial threads of both strains are interminglewith each other as shown in FIG. 5. However, the bacterial threads of‘Hokuto-18’ take against the other control strains as shown in FIGS.6–9. That is, the new variety ‘Hokuto-18’ expressly is geneticallydissimilar to the existing varieties similar to ‘Hokuto-18’.

As is apparent from the foregoing description, the new variety‘Hokuto-18’ according to the invention is apparently distinct inmorphological trait character from the other similar varieties and isexquisite in stability, reproducibility and uniformity in comparisonwith the existing varieties of this sort.

1. A new, distinct variety of Bunashimeji mushroom as substantiallyillustrated or described in the specification.